To study the factors and regularities affecting the penetration depth of steel target subjected to impact by deflagration-driving-type nail

the penetration process of 20 mm thickness Q235 steel target by 7 mm diameter nail was studied with numerical simulation. The Johnson-Cook constitutive model and the Gruneison state equation were used to simulate the penetration process of nails into steel target based on LS-DYNA finite element software

and the rationality of this model was verified through penetration test. Using the established simulation model

the influences of the cone angle of the nail’s nose

material strength of the nail

deflagration driving force

and the initial gap between the nail and the steel target on the penetration depth of Q235 steel target were analyzed. Results indicate that with the increase of the cone angle of the nail’s nose and the increase of penetration resistance

the maximum speed of the nail was decreased

so the penetration depth and the effective penetration depth were continuously reduced. When the static yield strength of the nail was less than 700 MPa

the penetration depth was relatively shallow due to the obvious mushrooming deformation of the nail

and when it was higher than 700 MPa

the static yield strength of the nail had little effect on the penetration depth. When the pressure produced by the deflagration was less than 150 MPa

the penetration depth increased approximately linearly with the increase of pressure

and when it was higher than 150 MPa

the stress was released due to the deformation of the back of the target plate

and the penetration depth was significantly improved. With the increase of the initial gap between the nail and the steel target

nail could achieve higher velocity before touching the target plate

and the penetration depth was increased

but when it was more than 20 mm

the initial gap no longer affected the penetration depth.